How to Use One AI to Prompt Another AI
How a planner model writes the brief and a builder model carries it out, and where that breaks.
Yes. You can use one AI to write the brief and a second AI to carry it out.
At Layer3Labs, we build and run AI workflows for small and mid-sized businesses, and the failure we hit most often is a missing hand-off format between steps.
Use it when a task is too large or vague for a single prompt.
Before scripting automated calls, test the hand-off manually by copying the planner model's brief into the builder model.
How One AI Writes the Brief for Another
Prompting one AI with another works by splitting a workflow into a planning stage and an execution stage, where a planner model drafts the brief that a builder model carries out. The trigger to separate models is a task too large or ambiguous for a single prompt.
The sequence has three hops: the planner writes the brief, the builder executes only that brief, and a person or a second check reads the result before it is used. To run it you need a brief template with a definition of done (the stop condition) and a review step. Build one hand-off by hand before any automation.
- Planner: writes the brief.
- Builder: executes only that brief.
- Check: a person or a second check reads the result.
Four Workflow Patterns for Chaining AI Calls
Anthropic names these workflow patterns in its "Building effective agents" article (published December 19, 2024), including the four below. Selecting the correct pattern depends on whether project subtasks are predictable or dynamic.
Prompt chaining decomposes a task into a sequence of steps, where each LLM call processes the output of the previous one. Anthropic notes that this fits tasks that can be easily and cleanly decomposed into fixed subtasks. Routing classifies an input and directs it to a specialized followup task.
For dynamic objectives, the orchestrator-workers pattern employs a central LLM that dynamically breaks down tasks, delegates them to worker LLMs, and synthesizes their results. Anthropic notes this pattern is suited to complex tasks where you cannot predict the subtasks needed in advance. Finally, the evaluator-optimizer pattern features one LLM call generating a response while another provides evaluation and feedback in a loop. It works when you have clear evaluation criteria and when iterating adds measurable value.
- Prompt chaining: decomposes a task into fixed sequential steps where each call consumes prior output.
- Routing: classifies inputs to direct requests to specialized downstream prompts.
- Orchestrator-workers: a central model delegates dynamic subtasks to worker models and synthesizes the outputs.
- Evaluator-optimizer: one model drafts output while a second provides structured feedback loops against explicit criteria.
Specialized Subagents in Claude Code
Claude Code includes subagents as a built-in way to hand a task to a separate assistant with its own context window. According to the Claude Code subagents documentation, subagents are specialized AI assistants that handle specific types of tasks. Each subagent runs in its own context window with a custom system prompt, specific tool access, and independent permissions.
Developers define a subagent by creating a Markdown file with YAML frontmatter containing required name and description fields. Saving this file in .claude/agents/ applies the configuration to the current project, while saving it in ~/.claude/agents/ makes it available across all local projects. The Markdown body beneath the frontmatter serves as the system prompt, and users can also supply subagents for a single session using the --agents command line interface (CLI) flag.
- Configuration: defined as Markdown files containing YAML frontmatter with mandatory name and description fields.
- Project scope: saved in .claude/agents/ for project-specific use or ~/.claude/agents/ for system-wide availability.
- Session override: injected temporarily into an active CLI run using the --agents parameter.
- Context isolation: each subagent runs in its own context window.
What a Planner Brief Contains
A practical hand-off between two AI models uses a standardized brief containing five specific operational fields. When the planner model finishes drafting, the builder model must receive only this structured brief rather than the full conversational history.
In practical workflow implementations, a human reviewer or a second check reads the result before it is used. This brief template provides a working pattern rather than a vendor guarantee.
- Goal: the deliverable the builder model must produce.
- Context: reference materials and necessary context for execution.
- Constraints: boundaries on what the builder may and may not do.
- Output format: structural requirements defining the format of the output.
- Definition of done: an objective checklist that the reviewer uses to verify the completed work before acceptance.
Where Planner-Builder Hand-Offs Fail
Because an execution model treats instructions from a planner model as verified truth, a confident but incorrect brief leads directly to flawed output. Errors compound across hops because each model trusts the last.
A second operational failure occurs when critical context disappears during the hand-off. The builder model maintains no memory of the original conversation, meaning any nuance or implicit constraint that the planner model omits from the brief is lost.
System latency and computing expenses also multiply with every additional model invocation. Each extra call adds cost and time. This is editorial reasoning, not a measured figure.
- Context truncation: subtle constraints omitted from the intermediate brief cannot be recovered by downstream models.
- Accumulated latency: sequential model calls add delay with each extra call.
Scenarios Where a Single Prompt Suffices
Single-prompt execution is preferable whenever a task can be stated with clear inputs and resolved within a single context window. Operators handling those jobs should use a single well-structured prompt in an interactive chat session rather than building complex pipelines.
A single model stops being enough when you cannot predict the subtasks in advance.
If a single well-written prompt gets the accuracy you need, skip the extra models. The AI prompt generator builds one.
First Steps to Connect Models Manually Before Automation
The first step to establish a multi-model workflow is testing the hand-off manually across separate application windows before writing any code.
First, ask a planner model to write a brief. Next, paste only that brief into a builder model in a fresh session.
After testing the manual hand-off, decide whether an orchestration framework (see LLM orchestration) or a Claude Code subagent would save you the copy-paste. Run one manual hand-off this week, then decide whether to automate it.
- Run the planner: generate a structured brief in your initial chat session using a five-part template.
- Conduct human review: verify that the generated brief contains all necessary constraints and context.
- Execute in isolation: paste only the brief into a fresh model session to evaluate builder performance.
- Evaluate done criteria: check the completed output against your checklist to identify dropped instructions.
Frequently Asked Questions
- You can use an AI model to write the system prompts, briefs, or instructions used to configure another AI model or agent. A Claude Code subagent is a Markdown file whose body becomes its system prompt, so a planner model's output can be pasted into that file.
- A person can paste one product's output into the other, or script the hand-off between the two. This page does not claim the two products integrate. If you script the hand-off, check each vendor's current terms and documentation first.
- A working pattern is a brief with five parts: goal, context, constraints, output format and a definition of done. This is an editorial pattern, not a guarantee from Anthropic. The AI prompt generator can draft one.
- Yes. One model can write the brief and a second can carry it out. Anthropic's Building effective agents article names prompt chaining, routing, orchestrator-workers and evaluator-optimizer as patterns for chaining LLM calls.
- The main operational risks include compounding errors where an incorrect brief misleads downstream models, lost context when a planner omits subtle constraints, and increased cost and latency across chained calls. A person or a second check reads the result before it is used.
- Whether using a small model to draft prompts reduces total expenses depends on each provider's current API pricing, token volume, and how many extra calls the pipeline requires. Check each vendor's current pricing page for the two models you plan to use. No figure is given here.
Need Help Connecting Multi-Model AI Pipelines?
At Layer3Labs, we audit operational workflows and build reliable hand-off architectures between models, ensuring your systems run with structured review gates rather than unmonitored prompt loops.
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